TRIBOLOGY

Tribology is the branch of science and technology concerned with interacting surfaces in relative motion, friction, wear, and lubrication. Peter Jost (1966) chairman of a working group of lubrication engineers introduced and defined the term tribology in the "Department of Education and Science Report” published in England.   This report suggested that British industry and government by improving the lubrication practices could save considerable amount of money. The field of tribology is extremely diverse with challenges in many different areas of study including: materials science, fluid dynamics, contact mechanics, dynamics, heat transfer, chemistry, physics, controls, surface characterization, and many more, (Davis & Hu 2009).

The development of internal combustion engine forced the experts to develop the system platform of engine tribology design where the problem of engine tribology could be analyzed and the function module of software system and frame work of whole system could be designed. The collaboration of different software and experts helped to improve the analysis ability and the knowledge on engine tribology (WANG et al. 2009).

The inherent elastic properties results in detachment waves also termed as Schallamach waves development in sliding polymer-polymer surface contacts and these waves helps in initiation and propagation of wear along the sliding contacts. Ashraf et al. (2007) used finite element quasi steady-state analysis of such sliding surfaces. The nodal solution for pressure obtained for small sliding steps of the developed contact model and analysis of orthogonal pressure components at the contact nodes reveals the formation of Schallamach wave phenomenon. Further, appropriate wear law is used for calculation of wear at nodal level.

ANSYS, a general purposes finite element modelling and analysis package is used to solve variety of mechanical problems as static/dynamic, structural analysis (both linear and nonlinear), heat transfer, and fluid problems, as well as acoustic and electromagnetic (Stolarski, Nakasone & Yoshimoto 2011).

ANSYS used in this research can also be utilized to handled Material and structural non-linearities, i.e., plasticity, viscoelasticity, and friction. As far as the contact problems are concerned the stated software present Lagrange multiplier, penalty function and direct constraint approaches to model contact conditions with different types of contact element. When meshing a model, the nodes on potential contacting surfaces comprise the layer of contact elements whose four Gauss integral points are used as contacting checkpoints, (Ashraf et al. 2009).

As the wear occurs when the surfaces are in contact with each other, it is utmost important to know how much material is lost in the given operation time.  The pressure distribution depends upon the surface shape in contact which may vary due to their function, manufacturing tolerances etc and are subject to change due to wear and plastic deformation. It’s the versatility of finite element method that it solves the stress and strain problems regardless of the geometry of the body.  In this paper, ANSYS 5.0A has been used for the Finite Element analysis of contact pressure determination and wear simulation. (Põdra & Andersson 1999).